Witcher 1 is still the best of the trilogy despite the problems though.
I'm not sure if I could pick a best Witcher game. The series as a whole is definitely one of my favorites though.
I really like the plot in TW1, and it has one of my favorite soundtracks of any game, but the aforementioned backtracking does bring it down a bit.
TW2 has the most significant C&C and the best combat in the series. It's a little on the short side though, and the bestiary isn't as varied as the other games.
TW3 has the best writing and characters but is brought down somewhat by the terrible loot system.
Overall I think I liked 2 the best. The overall story has better pace and structure, although the highest point of Witcher 3 is better (The Baron and the witches arc).
I enjoyed the combat in both, although is very flawed. But for a RPG worked well.
Size of the areas in W2 were the correct one to avoid pointless hiking, but interesting to explore. The world in 3 was very well executed for its big size, but I'm not a big fan of open world games these days.
The worst aspect in W3 is the loot, I agree. The diablo style scaled loot was a shitshow. Whit a proper equipment and weapon system the exploration would have been much better. That would have improved the sense of the world. It was cool idea to search for areas with legendary witcher loot, but 1 hour after that equipment is obsolete, and not only that, but everthing you find is pointless compared to that witcher equipment, no matter what, really stupid.
Character progression was dull in both, but doesn't avoid game enjoyment. I have to make one day a potion build inW2, that seems the proper one and more fun than focus on magic mastery.
Overall the games are greater thant the sum of their parts. But except for story they are every inferior to the king Dragon's Dogma.
I agree with everything you said there except for the very last sentence.